GERYDUS. By H. Fruhstorfer. 
821 
band, from the upper end of the cell advancing somewhat distally, traverses the disc as far as the middle median 
where it grows broadest, whence it tapers off in order to vanish at the posterior median.“ The band is broader 
than in G. biggsi Dist. Hind wings entirely dark. Underneath the white band of the forewing is dark and broken, 
the spot in the lower median-interspace is isolated and more distinct than the rest. A transverse band com¬ 
posed of crescents, on the forewing, is obsolete. Besides there are three costal ring-spots and three minute 
subapical moons. Hindwings less extensively clouded with black than G. croton Doh. The transverse band 
nearly regular, the basal spots square, those of the submarginal zone very distinct. The $ larger than symethus-3, 
not quite so large as G. ancon. The anterior median above bare and, beginning from the cell-end, thickened 
to one fourth of its length. Malayan Peninsula. Unknown to me in nature. 
G. archilochus Fruhst. (141 b). G resembling Allotinus multistrigatus Nicev. by its intensely smoky- 
brown colouring and its size. Forewing with a yellowish-scaled sexual spot at the base of the anterior median. 
$ above similar to the $ of multistrigatus ; the hindwings less sharply dentate. Colouring somewhat lighter 
than in the <$. The forewing with a rounded arc scaled in a yellowish white, beginning beyond the cell and ending 
at the submedian. Under surface grey-brown with the scent-spotted, black basal area peculiar of the Gerydus 
symethus-growp , which is bordered with a dull white in the posterior part. The macular series of the under 
surface arranged similarly as in leos Guer., though more conspicuous, particularly in the $ very broad and there 
also lighter brown than in the <$. Tonkin, Man-Son Mountains, at an altitude of 800 m, in April-—May. 
G. symethus. The best-known species of the whole group. The $$ are very variable and there seem 
to occur almost everywhere specimens with a nearly entirely white disc of the wings and also such with trans¬ 
verse grey median streaks. The hindwings vary in the colouring above from a monotonous black-brown to 
whitish or grey, even greyish-violet. The $ differs above considerably from the the hindwings being almost 
square are sharply angled. The forewings are nearly always white, the hindwings vary according to the habitat 
from a chalky white to a greyish blue. The under surface in both sexes remains more constant. The only 
variability is exhibited by the extent of the white median zone which, again according to the habitat, may 
be of the shape of a band or cover large spaces. Hindwings of the preponderantly grey, those of the $ 
extensively shot with yellowish. Most remarkable is besides a black basal spot which is present in the and $ 
and varies in a hardly perceptible way. Uncus sheets very long, with a feeble dorsal indenture. The small 
ventral hooks, considering the size of the imago, of a remarkably delicate structure, strongly contrasting with 
those of G. melanion and G. leos. Valve remarkably small, though in contrast with G. leos with a noticeably 
separated apex. The butterflies preponderantly inhabit the forests of the lowlands. I cannot remember of 
having come across them in Java at altitudes of more than 5 to 600 m above the sea-level. They are fond 
of the skirts of the woods or of roads in the jungles, and like to rest on the upper surface of leaves, where 
they perform jerky movements. They are, however, very lazy and disappear in the thicket on being disturbed. 
According to Moulton, Shelford saw in the Botanical Gardens of Singapore some ants on a large leaf moving 
round a $ of G. symethus. On a closer examination he found that both the Gerydus and the ants were drinking 
from the secretions of the anus of small larvae of Fulgorids or Jassids. The larvae remained all quiet, as long 
as the guests were drinking from them; they, however, jumped down from the leaf, when they were disturbed 
by Shelford. Range of the collective species from the Naga and Karen Hills through Macromalayana, some 
Philippine Islands as far as Lombok. — diopeithes Fruhst. (141 d) was observed in the Mergui Archipelago, 
in Tenasserim and the Naga and Karen Hills. The name-type originates from the Malayan Peninsula; there are 
also specimens before me from the Riow-Archipelago. characterized by the great extent of the white discal 
area of the forewing. upper surface of the hindwing lighter than in Sumatran also the under surface 
paler. — acampsis Fruhst. North East Sumatra. The white spotting of the forewings is more sharply defined 
than in symethus. Hindwings black. The white zone of the under surface narrower than in any vicarious type. 
upper surface of the hindwings uniformly grey-blue, without any purely white stripes like in the Java-race 
and never of a pure white as in perlucidus from East Java. Under surface more uniformly red-brown than 
in symethics. — bangkanus Fruhst. Island of Banka, type in the Coll. Adams of the British Museum. <J smaller 
than from Sumatra and Perak. Under surface of the forewings with a considerably narrower white intra- 
median band. Hindwings brightened up by yellowish, therefore resembling much more the Javanese vicarious 
type than acampsis Fruhst. from Sumatra. — batuensis Fruhst. Type from Pulo Tello of the Batu Islands in 
the Coll. Adams of the British Museum. $ considerably smaller than of G. acampsis Fruhst. from Sumatra. 
Under surface exhibiting the melanism of the satellite islands by the darker ground-colour of both wings and 
the extent of all the black maculae. -—- vespasianus Fruhst. (141 d). Nias. A remarkable insular form. Habitus 
smaller than the preceding; both sexes are coloured almost quite the same. The black margin of the hindwings 
is dying away, that of the forewings, particularly in the beginning only beyond the cell. — symethus Cr. 
(141 d). The name-type is denoted to originate from India, though it has pretty surely come from Java. West 
Java up to 800 m. d'-fm pandu Horsf. differs from the common examples "as we figure them, by a more extensive 
white discal area of the upper surface of the forewings. The $ has a stripe-like brightening confined to the 
cell, on the hindwing. — perlucidus Fruhst., from East Java, differs from the preceding by the hindwings 
of the (d being brightened up by white in the posterior parts. The discal area of the forewing is still more 
archilochus. 
diopeithes. 
acampsis. 
bangkanus. 
batuensis. 
vespasia¬ 
nus. 
symethus. 
pandu. 
perlucidus. 
